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Explora: Environment
and Resource Environmental contamination of titanium

the accumulation rate of Ti in the environment and
mitigate associated environmental risks. 148
The National Institute for Occupational Safety and
Health (NIOSH) classifies TiO as a potential occupational
2
carcinogen. However, in response to growing concerns over
TiO NPs’toxicity and the evidence of TiO carcinogenic
2
2
qualities in animal studies revealed by IARC, France has
started a classification process under European Regulation
(EC) No.1272/2008. 118,149 According to the Toxic
Enforcement and Safe Drinking Water Act administered
by the Office of Environmental Health Hazard Assessment
of the California Environmental Protection Agency, the list
of chemicals known to cause cancer, created in 1986 under
Proposition 65, was revised on September 2, 2011. 118,150
This list was expanded to include respirable TiO airborne
2
particles. The US Food and Drug Administration has
151
allowed TiO as a food additive as long as its content is less
2
than 1% of the food’s weight. Similarly, as long as acceptable
manufacturing procedures are adhered to, the EFSA also
permits TiO as a food additive with no maximum limit.
33
2
According to time-weighted average concentrations, the Figure 4. Technologies for the removal of titanium (Ti) from
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USNIOSH recommends exposure limits of 2.4 mg/m for aquatic and soil environments. Created with Edraw Max by
Xiaodong Yang (2025) https://www.edrawsoft.cn/viewer/public/s/
“fine TiO ” (including pigmentary TiO ) and 0.3 mg/m for max/578fc91242b811f0aadcfda6796e95fb.
3
2
2
“ultrafine TiO ” (including nano-TiO ) for up to 10 h/day
2
2
over a 40-h workweek. 149,150 Additional detailed discussions limit the mobility of Ti in soil and groundwater sources;
on regulatory measures regarding the use of TiO in conversely, Ti’s solubility and mobility are increased when
2
consumer products are beyond the scope of the present it complexes with both inorganic and organic ligands. The
review. current review summarizes the sources, biogeochemistry,
and its effects on the environment and human health, as
In the environment, the most prevalent oxidation state well as suggests future research areas of concern. This work
of Ti is the Ti(IV) ion, which shares similar characteristics also addresses Ti contamination’s potential advantages or
with aluminum(III) and iron(III) ions, including the ionic disadvantages in comparison to other materials, although
radius. Therefore, the removal of metal elements, such as
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aluminum and iron, can serve as a reference for Ti removal there is a clear focus on negative impacts. Ti is considered
(Figure 4 and Table S5). In soil, Ti predominantly exists in a non-essential element for plant, animal, and human
a stable form, with limited concentrations in itsavailable nutrition and is not toxic at low levels of uptake. However,
state and restricted uptake of NPsby plants, thereby making excessive Ti uptake can cause toxicity to plants, soil
phytoremediation the primary approach for remediating organisms, aquatic life, animals, and humans. For example,
elemental Ti and nano-Ti. 34,152 More details are discussed dust inhalation of TiO NPs by humans has resulted in
2
in Supplementary Information 2. chest pain, coughing, and breathing difficulty. There are
several methods for remediating Ti-enriched aquatic
6. Conclusion and future research and terrestrial environments, including ion exchange,
directions flocculation, adsorption, phytoremediation, reverse
osmosis, and nanofiltration.
Although Ti is found naturally in certain mineral forms,
such as rutile, brookite, anatase, ilmenite, and titanite, Increased mining and processing, along with the wide
paints, nanomaterials, and wastes from mining and application of Ti, have raised concerns about its pollution
industrial processing are the primary anthropogenic in the environment. TiO particles are traditionally known
2
sources of Ti accumulation in terrestrial and aquatic to have low solubility and toxicity, and have been used as
ecosystems. In general, Ti comes from terrestrial negative controls in many in vivo and in vitro toxicological
environments, such as ore. However, low mineral solubility analyses. Thus, Ti is not only a metal likely to see increased
and relatively strong adsorption onto soils and sediments use but also potentially an emerging contaminant in the

Volume 2 Issue 3 (2025) 15 doi: 10.36922/EER025130027